


The Demon's Contract

by Kushu



Category: Death Note
Genre: F/M
Language: English
Status: In-Progress
Published: 2014-09-14
Updated: 2014-11-23
Packaged: 2018-02-17 08:16:24
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 4
Words: 4,841
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2302832
Author URL: https://archiveofourown.org/users/Kushu/pseuds/Kushu
Summary: <blockquote class="userstuff">
              <p>The daughter of the Demon King is out for L's Soul. But first, she has to fulfill L's wishes and help him defeat Kira. A contract is made and a deal is born.</p>
            </blockquote>





	1. Breakout

**Author's Note:**

> I have previously posted this on fanfiction.net two years ago. This is a rewrite and hopefully improved.

I was simply intrigued. By his past. By his mannerisms. By him. He solves mysteries not for justice, but because he was bored. I had read about a similar detective by the name of Sherlock Holmes a century ago. Except, L is real. I want to meet him someday – no – I _need_ to meet him someday. But in my current state, I cannot simply visit the human world. I have yet to learn how to suppress my demonic powers. If I were to go without a strong vassal, I would certainly wreck havoc there. Everything there is fragile to the touch.

I have watched L all his life, and he never fails to entertain me. Not only is he entertaining and intriguing, his soul is quite… unique. He seems to be all-knowing on the outside… but on the inside he's like a confused and lonely lost child. A child. That's all he is.

Slowly, I sat back on the cold stone chair provided by my father. He has confined me in the dungeons because not too long ago, I possessed a human girl in order to meet L. Let's just say her body didn't even last long enough for me to even blink with it. Naturally, she convulsed and died right there, and I was ejected from her. Poor thing.

"Father! Let me out! This is ridiculous!" I roared loudly and punched the bricked walls once again. If only they weren't like three yards thick, they would have given in. Instead, I created a hole the size of a dinner plate. Over the past week, I've created clusters of holes on these damned walls that kept me imprisoned. How could a princess be treated in this manner?

"At least give me food! I'm hungry!" I shrieked, banging violently on the walls again.

"Mistress, please calm down," one of the guards had came down to give me one of those pep talks again.

"Fuck off, you little bitch." I growled viciously through my gritted teeth. I can feel the electricity crackle around my skin. _Oh no_. Noble demons such as myself tend to have control over certain elements. For me, it's the ability to manipulate electricity and even fire. As I am inexperienced in the stabilization of this power, it can get pretty unpredictable when I am furious. And oh boy am I _furious_.

"I apologize, young Mistress. The Lord forbids me to," The demon guard came closer into view with a food tray in hand. He slid the food through the tiny slot of the steel door. "However, please enjoy your food."

I flushed in anger. Is this guy trying to toy with me? "Release me right now or I will have you beheaded and fed to my pets!" I shrieked once again. The electricity crackled more. Louder this time. I punched the steel door, denting it more that I did last time. _Crackle_.

In place of a response was the sound of footsteps walking away from my cell. Damn it all. _Crackle. Crackle._

"LET ME OUT!" I screeched. I bared my sharp teeth viciously and roared. Every _akuma_ in the demon realm must have heard it. Suddenly, I felt every inch of my body getting hotter by the second. Electricity crackled all around me, but it didn't tingle. Nor did it sting. Instead, it empowered me. I know I was in an unstable state at the moment, but when I am enraged, there's no stopping this.

My body transformed into its true form. It's actually quite gruesome and unladylike. My soft brown hair grew longer and turned into a bloody color, making it look like flowing strands of blood. Every single tooth in my mouth changed into sharp, animal-like teeth that can cut through the strongest of metals. Black leathery wings sprouted from my back and stretched across the cell. Sharp nails morphed into claws that could cut any human (or demon for that matter) in half with a single motion. All my senses were respectively heightened.

I was a beast. A true monster.

The cell, unable to handle any more of my demonic energy, exploded. I was free.

Like I said, I can't suppress my demonic powers and therefore cannot go to the infamous human world. But there is a way that I can. Demons are known for their deals and contracts aren't they? All I have to do is to make a contract with L, but it's easier said than done. It's not very likely that L would even make a contract with a demon. But, I am, after all, the Demon King's daughter.

 _L Lawliet, I'm coming for you_.


	2. December 30, 2003

Flying to the Black Market, heading to a store that belonged to an old friend of mine, I calmed myself down quite a bit and turned back to my usual form. "Xalba! Are you here?" I yelled into the store. It was a tiny one, cluttered with all kinds of demon-made weapons and cursed jewels.

"Who is it?" He yelled back. I then heard some items crashing smashing on to the ground as Xalba came out. "Lady Thanatia!"

"Stop it with the formalities. We both know that I am nowhere near a lady," I scoffed. Xalba and I have known each other all our lives, and believe me; demon lives are pretty much eternal (with a few... exceptions). He's an awkward lower-level demon who doesn't really associate with the more aristocratic higher-level demons. I suppose that I'm the only exception since we became friends without him knowing that I was the demon 'princess' and well, now he's stuck with me. "Anyway, do you have some extremely powerful Suppression Necklace?"

"A Suppression Necklace? You're not trying to go to the human world, are you? I heard that last time you went, you-" He stopped himself as he saw the vicious expression on my face. "One extremely powerful Suppression Necklace coming up."

"Why thank you, dear." I said in a sickly sweet voice and smiled. "Also, would you be so kind as to open a portal to the human world? My father took away my portal key."

"Of course. Here's your necklace, and I will open the portal for you shortly," He handed me the necklace and I felt weak just touching the thing. Suppression Necklaces drain your energy and traps it in the ruby pendant that hangs from the chain. If you want your powers to be restored, you must have the owner smash the necklace pendant. It is used to drain powers of other demons, but sometimes unstable demons, such as I, use it to sustain their own powers in order to visit the human realm. You might ask why I did not do this sooner to avoid killing that innocent girl. Well, this method is just extremely uncomfortable for me and I cannot use my powers to its extent with such a large amount of my energy drained.

I felt a harsh tug at my body, and realized that Xalba had already opened the portal. I clumsily put on the necklace and went towards the portal.

"Thanks, Xalba! I owe you one!" I yelled, stepping into the portal.

"You owe me plenty, now leave!" He said, laughing to himself. And just like that, I was pulled into the human world.

 

* * *

_  
_

I was literally thrown down to the empty streets of Japan. It was fairly dark outside, and considering the silence that seems to linger, I deduced that it was about one in the morning here. I tilted my head up to sniff the fresh air of the human world. Something… smelled sweet. My legs unconsciously moved towards the direction of the smell. After wandering around for about thirty minutes, I reached the entrance of a hotel where inside, you can see the receptionist slowly dozing off. Humans can't see me unless I want them to, so I swiftly opened the door and walked right in, still following the smell. No one had seen that, I'm sure. Unless those pesky humans had installed those annoying cameras. Next thing I knew, I was in front of a door of one of the hotel rooms. _Sweet_.

I knocked on the door as a formality and listened carefully for any sign of humans inside the room. I heard nothing, except some very quiet creaking, and so I broke the door knob and entered. As I entered, I heard a peculiar scream that sounded flat, yet frightened. So there were humans in there after all. I focused my eyes on the human and he looked at me with fear. He can see me? I looked at his face closely and… he was L. It's got to be. The aroma was so sweet, I couldn't take it.

My body moved on its own, towards L. Demon instinct took over and I can feel my canines protruding from my mouth, slightly grazing at my lower lip. My eyes felt hot, and I knew that they had changed to the color of blood. _So_ _sweet_. I moved closer. L started darting away in a swift movement and took his stance, indicating that he would attack if he had to. I quickly snapped out of my daze.

"L," I said, and then smiled innocently. As innocent as a demon could look with her sharp canine teeth. "I apologize for being rude, and barging in. But please let me introduce myself."

L stared at me inquisitively, and regained his control, but I felt his fear. I assumed that Watari was not here at the moment. But if he was, there wasn't going to be a problem since Watari can't see me unless I wanted him to. Though it would be quite strange if he saw L talking to an invisible force. "I am Thanatia Savan Luchesi de Sondra, daughter of the Demon lord. I have come… to form a contract with you, L." I said professionally.

"A contract? Interesting," he said cautiously, never breaking eye contact. He stood up and walked towards me, swung his leg and kicked. I swiftly dodged and he missed. "More interesting."

"Well? Isn't there something you'd like? I can fulfill your wishes to the extent of my powers. With the low, low price of your... soul." I said calmly and went to sit on one of the chairs present as if he hadn't tried to assault me with his foot in the first place.

"Something I'd like… for the exchange of my soul?" He said thoughtfully to himself and brought his thumb up to his lip, gently nipping on it. "No, thank you. What a ludicrous thing to say. Please leave before I have you arrested for trespassing."

 _How_ _cold_. "Kira," I began. "He can't kill you as long as you make this contract with you. You wouldn't want to lose to Kira by dying would you?"

The look on L's face made it seem like I had exposed his one weakness. "I suppose winning would be most agreeable, but…"

"Okay… I don't think I made it very clear. You will make a contract with me, L." I said menacingly, advancing towards him. My anger rising quickly. "Now, there are some demons that aren't allowed to kill humans, but I'm not one of them. So don't upset me. Either you die now, or you die after you win the game. Choose."

"Why _ask_ me for a contract in the first place? So pretentious, you are." he said, barely holding onto his calm composure. "Are you some sort of criminal cosplayer?"

"Look, I don't have time for your jokes," I shot back and my feet left the ground to hover towards him. "See? I'm supernatural. Not a criminal cosplayer."

L's expression changed to that of a mix between surprise and horror. "Oh my..." He whispered.

"If we make the contract, I will do as you command. But the moment your true wish has been fulfilled, your soul will be mine for the taking," I continued, feeling smug. "Do you wish to form the contract?"

"I don't have a choice…" He said, stalling.

"Do you _wish_ to form the _contract_?" I repeated those words harshly.

"Yes, I wish to form the contract," He said, feeling hesitant.

"Oh, come on… say it like you mean it," I teased and grinned from ear to ear. "I'm waiting…"

"I wish to form a contract," L said resolutely while his eyes bored into mine.

"As you wish, master," I purred and curtsied respectfully to my new _master_ like a good little demon princess would.


	3. Instinct

I sat idly by as L typed furiously on his laptop with his long and slender fingers. Once in a while, he would reach for his cake and the donuts from the sweets tray which lie right next to him. After we had formed the contract that day, he informed me about his current knowledge about the Kira case. It sounded like something oddly similar to the effects of the Death Note that the Death Gods possessed. I couldn't be sure since I haven't taken my time to research the Death Gods. It could be the works of another demon for all I know. For now, I told L nothing of my theories until I am sure of it.

Either way, those opposing forces can be easily evaded. If it was the case of the Shinigami, which I suspect most of all, then they can't take away L's life as I have already claimed his soul. At least... that's how it works, right? I was here first so those losers need to back the hell off my delicious soul. As for other demons causing havoc, I have the power to punish them. After all, the only demons with the power strong enough to defeat me are my older siblings and my parents.

"What's wrong?" L asked as he picked up a donut from the tray. "You seem to be deep in thought. Would you like a donut?" He handed the donut to me without taking his eyes away from the computer screen.

"Nothing, I'm just… theorizing." I said and then took the donut in my hands. I didn't know what to do with it. Do humans eat this sort of things? All we demons eat are human souls, anyway. I took a cautious bite out of the donut and then gobbled the rest down in five seconds. _Mmmmm_ , _delicious_. "THIS IS DELICIOUS!"

"Glad you liked it." he said monotonously and continued to eat his piece of cake. Bored, I stood and walked up behind L. I draped my arms down his front and lowered my head on his shoulder and took in his scent. L stiffened. _Sweet_. I can feel my demon canines protruding from my mouth yet again.

Unconsciously, I opened my mouth and nipped at the nape of L's neck gently. He let out a gasp of pain, broke free from my grasp and leaped away from his seat. "What are you doing?" He questioned. His face was clearly red.

"I was… bored," I said truthfully. "Whoops."

"Please refrain from sexual harassment, demon. It is most unpleasant." He replied uneasily and then went back to perch upon his seat.

"I'm sorry… It's just that… I can't wait to eat you up," I said innocently, and laughed as L went back to type on his laptop. Suddenly, Watari's insignia appeared on the screen, breaking whatever mood I had.

" _L,_ _you_ _know_ _what_ _to_ _do,_ " Watari's voice said. " _I_ _will_ _now_ _connect_ _you_ _with_ _the_ _ICPO_ _members_ _that_ _are_ _willing_ _to_ _work_ _with_ _you_ _on_ _the_ _Kira_ _case,_ "

"Very well, Watari," L spoke into his microphone. "It is only you, with your strong convictions, that I can trust," L said to the ICPO members presumably present behind the screen.

" _Wait_ _a_ _minute_ ," I heard one of the men say. " _L_ _said_ _that_ _he_ _trusts_ _us_ _…_ _But_ _we_ _don_ _'_ _t_ _trust_ _him!_ _"_

Grunts of agreement were exchanged when another one of the men said, " _L,_ _it_ _is_ _evident_ _that_ _we_ _'_ _re_ _determined_ _to_ _catch_ _Kira even_ _if_ _it_ _costs_ _us_ _our_ _lives!_ _That_ _means_ _that_ _we_ _all_ _understand_ _what_ _it_ _means_ _to_ _put_ _our_ _lives_ _on_ _the_ _line_ ,"

The man who spoke at first then said, " _But_ _you_ _just_ _order_ _us_ _around_ _without_ _showing_ _us_ _your_ _face!_ "

" _We_ _will_ _pursue_ _Kira,_ _but_ _not_ _with_ _your_ _assistance._ " another one of the man interjected. I scoffed. Who are they to look down on L? After a few interjections from the men, Chief Soichiro Yagami said, " _L,_ _if_ _you_ _'_ _re_ _willing_ _to_ _join_ _forces_ _with_ _us_ _and_ _capture_ _Kira,_ _come_ _to_ _the_ _headquarters_ _and_ _work_ _with_ _us_ _in_ _person_."

One of the men then declared his agreement to the statement. L's expression seemed perplexed as he contemplated. "Earlier, I said that I only trust you people," L began. He then typed in:  _What_ _happens_ _from_ _now_ _on_ _must_ _be_ _kept_ _between_ _the_ _eight_ _of_ _us._

"Watari," L said simply, as if signaling him to do something.

" _Yes._ " Watari said minimally and then I heard scratching noises that indicated that the laptop screen was being lowered around. Watari must be showing the men the message that L just typed.

He continued to type some more while I spaced out. I assumed that the issue had been resolved after the men were quiet and L stopped typing. "So, what's happening now?" I asked indifferently.

"I am to meet with these men. Unfortunately, that's the only way for them to trust me." L replied dejectedly, but nevertheless monotonous. "We are to meet tonight."

"L, I don't see why you need their help. I'm all the help you need. Those incompetent fools will be nothing but hindrances." I said.

"They will prove their use eventually." L replied simply. "Eventually."

_~ I N T E R M I S S I O N ~_

L stood near the window, seemingly contemplating yet again. I presume that it's about Kira. It's always about Kira, isn't it?

"L, why do you feel the need to pursue the Kira case?" I asked suddenly.

"Why? Because it interested me." He said passively. "Anyway, it's none of your concern to why I am pursuing the case. You are to help me solve it. Thus, any other type of information is trivial."

"Not in the mood to talk, are we now?" I said and proceeded to rummage through L's belongings. He didn't seem to mind my snooping for some reason. I felt like I could use a change in my usual attire. Maybe I should try on L's outfits and imitate his quirks for some amusement in the mean time. Yup. Sounds like a plan.

It's quite comical how L has a closet full of the same shirts and jeans. You would think that he wears the same shirt and the same jeans every day, but nope. There are duplicates, apparently. While L was distracted, I grabbed an outfit and went into the bathroom. I took off my clothes, looked at myself in the mirror and found myself frowning at my small chest. My revealing attire did nothing to make me look bustier. I had no sex appeal pretty much, but at least I have curves in the desirable places. Even so, my personality is more masculine than it is feminine, as you can obviously tell. Anyway, I swiftly changed into L's shirt and jeans and walked out of the bathroom.

"L! Look at me! We match." I said with a wide grin etched on my face. L's face looked slightly confused. He opened his mouth as if he was going to say something, but decided against it. L then turned back to stare mindlessly at the window with his thumb to his lip once again.

My wings (the small version, since I wasn't unstable) sprung out and I hovered over to L. As soon as he detected my presence, he went rigid as expected. I lowered my head to L's ear and whispered, "I said… we match."

L turned around and pushed my face away… with his foot. Hard. It would have hurt if demons' bones weren't as hard as steel. So it might have hurt him more than it did me. L cursed in pain.

"That hurt." He said.  _Well duh._

"I never told you to kick me." I replied. My tone was harsh because I can't believe that a human would have the audacity to kick me. The fact that he did not miss bothered me the most.

"I apologize, but it was because you—"

"Whatever. I'm out of here," I snapped. On an impulse, I whistled, calling out to my hellhound. I don't believe I've told you this before, but I own a hellhound. Yup. Those giant, black snarling monsters with gleaming red eyes. My beautiful hellhound appeared immediately, as if warped out from a small vortex, making the whole room smell like death and rotting corpses. "Good luck with your meeting. Tell me how it goes. I'm going out for a ride."

With that, I disappeared from the room, riding into the darkness of the night.


	4. Let There Be Light

**~ L's P.O.V. ~**

Why did she leave? I had not done anything wrong. Furthermore, she was the one who came onto me and it was completely natural to defend yourself. I'm sure she'll be back relatively soon. At least, I hope so. _Hope so_? Why would I be so eager to have her back? She is not of any importance to me. I will die at her hands after this case anyways, so I shouldn't be caring for her at all. It is illogical to do so.

Though, I suppose that she is quite entertaining…

Quite entertaining indeed.

**~ Thanatia's P.O.V. ~**

_Idiot, idiot, idiot, idiot_. Why did I run out like that? As a contracted demon, I have to stay at my master's side at all times.

"You can leave now, boy," I cooed and kissed the top of my hellhound's head. He barked affectionately and faded away into the shadows. _What… am I doing here_? Somehow, my hellhound had stopped in front of nowhere before I sent it away. Where was I? I kept hovering around until a rotten smell struck me. It was the smell of a corrupted soul and the stench of death. I'm sure it wasn't my hellhound since I had sent it back. What was it?

I hovered towards the smell, even if it sickened me to the core. Somehow, I ended up facing a house that had this lingering evil laced around one specific room. Demons? Death gods? Possessed human? What was this, exactly?

The name plate of the house clearly states _Yagami_. Yagami? As in Soichiro Yagami? No. It couldn't be. My curiosity has reached its peak, and so I just had to investigate. I transformed into an innocent high school girl whose clothes indicated that she had been attacked. My disguise is flawless.

Cautiously, I knocked on the door, wearing a scared expression on my face. Immediately, I heard some scuffling and the door swung open. I saw a handsome young man with chestnut brown hair… who reeked of a corrupted soul. Why was he up at this hour? Humans are supposed to be asleep at three in the morning, aren't they?

"P-please help me! I w-was at-t-tacked by these men! May I hide here?" I pleaded with utmost fear in my eyes. The young man's facial expression became sympathetic and seemed more… relieved?

"Of course, please come in," he said in a gentle voice and led me upstairs to his room. I can smell it as soon as I stepped into the neat room. I can smell death here. _Death God_.

"You can stay here for a while, I'll prepare some tea for you," he said politely, using the _keigo_ way of speaking. Which was strange to me since we were the same age. "By the way, what is your name?"

"My n-name is Aiko," I answered in a small voice and sat on the chair near a desk. "Aiko Tsukimori."

"My name is Light Yagami," he said and smiled innocently, "nice to meet you, Tsukimori-san."

And with that, he left the room and pulled the door to a close. Except, it didn't close completely. I presume that he is suspicious of me. For what, I have no idea. Though it is quite odd that you would let a suspicious person in your house. He is definitely up to something.

I definitely suspect him of being Kira. I have never smelled such a foul soul before. As of now, I have no evidence of him being anything. Unless… unless… the Death God decides to show himself. But the chance of that happening wouldn't be so high. The Death God might have taken a liking to the human, and will not reveal himself. With the stench of death swarming around the room, it is certain that a Death God is here in this very room. I must not falter. My disguise is quite strong, and I have taken necessary precautions to mask my smell as a demon. I appear and smell like a normal human.

Footsteps indicated that Light was coming back with "tea." Whatever that is. My facial expression had not changed. I still had to stay in character, acting scared and nervous. He set the tea on his work desk what was beside me.

"Y-yagami-san," I began nervously, "I am sorry to have intruded. You must have been sleeping."

"Well, I was staying up late to cram for school," he lied while I took the warm cup of tea in my hands. "It was no bother at all and I'm happy to help."

"Thank you s-so much," I said gratefully and took a small sip. Ugh, this "tea" tasted weird. Why couldn't it taste like donuts? I set the tea down on the desk. "I don't know what would have happened to me had you not helped me."

"Well, you can leave any time you want," he said nonchalantly and sat on his bed. I took advantage of that and walked towards him.

"Surely, you do expect me to repay you in some sort of way?" I suggested shyly. Humans are greedy creatures. They wouldn't help a person in need unless it benefited them in some way. Surely, he would be easy to manipulate that way.

"No, you don't really need to do _that_ sort of thing," he replied quite seriously.

"What sort of things are you thinking about? I was thinking that I treat you to a meal," I said and giggled, "I do have my dignity, you know. Unless… you want _that_."

He turned bright red. "N-no, I'll settle for the meal." He is kind of adorable, I must say. I leaned forward suddenly as if to walk towards him more. Light twitched cautiously at this motion, preparing to defend himself if necessary. But, I can see that this all an act. Even so, it is quite… cute. It makes me feel like the predator and him, the prey.

"You are so adorable," I said without thinking and took a step forward. I stepped on something wet and slippery (I assumed he had spilled some tea) and toppled over Light onto his bed. If his parents were to walk through that door right now, he would be in big, big, big, big, _big_ trouble. He didn't dare to move while in this position.

"Well, that was awkward…" I said and got up slowly. "I-I should get going. I'm pretty sure the men are gone."

"R-right," He replied slowly, as if dazed.

"I'll come back here soon, okay? I'll take you out for a meal," I said and smiled. "If you'd like."

"Yes, that'd be wonderful, Tsukimori-san," he replied with forced enthusiasm. "Is your house near here? If it is, I can walk you home."

"Well it's not near…" I said hesitantly. "Maybe I can stay the night? I don't think the train station is open. If it's too much of a bother, I can walk home by myself…"

Crap. Why did I ask for him to let me stay over night? I have no intentions of doing such things. Thanatia-sama does not and will not sleep at a stranger's home. A human stranger at that.

"I think you should walk home," he said. I felt relieved instantly. "Here, I'll give you my phone number. If anything happens, call me. Okay?"

"Okay! Thank you, Light." I said and did a soft, girlish giggle. "Don't forget, I'll be back soon."

Light walked me to his front door and we said our goodbyes. I even kissed him on the cheek as thanks. Little does he know, that kiss is a mark of a demon. When a demon has marked you, thoughts and feelings could be shared. Though, it's a one-way connection. Only I can hear his thoughts and feel what he feels. A kiss on the cheek isn't a very strong demon mark, so the thoughts and the feelings will be quite… blurry. But this will do for now.


End file.
